This invention relates to ink jet printheads. More particularly, this invention relates to an ink jet printhead that incorporates through-chip ink ejection nozzle arrangements.
The Applicant has invented an ink jet printhead that is capable of generating text and images at a resolution of up to 1600 dpi.
In order to achieve this, the Applicant has made extensive use of micro electromechanical systems technology. In particular, the Applicant has developed integrated circuit fabrication techniques suitable for the manufacture of such printheads. The Applicant has filed a large number of patent applications in this field, many of which have now been allowed.
The printheads developed by the Applicant can include up to 84000 nozzle arrangements. Each nozzle arrangement has at least one moving component that serves to eject ink from a nozzle chamber. The components usually either act directly on the ink or act on a closure which serves to permit or inhibit the ejection of ink from the nozzle chamber.
The moving components within the printheads are microscopically dimensioned. This is necessary, given the large number of nozzle arrangements per printhead. The Applicant has spent a substantial amount of time and effort developing configurations for such printheads.
One of the reasons for this is that, as is known in the field of integrated circuit fabrication, cost of on-chip real estate is extremely high. Furthermore, it is important that levels of complexity are kept to a minimum since these significantly increase the cost of fabrication.
Integrated circuit fabrication techniques involve what is generally a deposition and etching process. As a result, devices which are manufactured in accordance with such techniques are usually, of necessity, in a layered construction. Furthermore, it is important to develop a configuration where a high number of devices can be fabricated per unit area of chip surface.
The present invention has been conceived by the Applicant to address the difficulties associated with achieving the high packing density of the nozzle arrangements and thereby to facilitate substantial cost saving in manufacture.
According to a first aspect of the invention, there is provided an ink jet printhead chip that is the product of an integrated circuit fabrication technique, the printhead chip comprising
a wafer substrate having a front surface and a rear surface, a plurality of ink passages being defined through the wafer substrate, so that each ink passage defines an inlet at a rear surface of the wafer substrate and an outlet at a front surface of the wafer substrate, each ink passage being in fluid communication with an ink supply at the rear surface of the wafer substrate; and
a plurality of actuators that are positioned on the rear surface of the wafer substrate and are operatively arranged with respect to the ink passages to generate an ink flow through each passage, from the rear surface to the front surface, when activated.
According to a second aspect of the invention, there is provided an ink jet printhead chip that is the product of an integrated circuit fabrication technique, the ink jet printhead chip comprising
a wafer substrate;
a plurality of ink passages defined through the wafer substrate, so that each ink passage defines an inlet at a rear surface of the wafer substrate and an outlet at a front surface of the wafer substrate, each ink passage being in fluid communication with an ink supply at the rear surface of the wafer substrate;
roof walls, side walls and floor walls that are positioned on the rear surface of the wafer substrate to define a plurality of nozzle chambers, each roof wall defining an ink ejection port that is in fluid communication with a respective ink passage; and
a plurality of actuators that are positioned on the rear surface of the wafer substrate so that each actuator is operatively arranged with respect to each nozzle chamber to eject ink from the nozzle chamber and out of the ink ejection port.
The invention is now described, by way of examples, with reference to the accompanying drawings. The specific nature of the following description is not to be construed as limiting the scope of the above summary, in any way.